1. Field of the Invention
The present invention is generally in the field of dielectric materials. More specifically, the invention is in the field of dielectric ceramic materials.
2. Background Art
Dielectric ceramic compositions, such as dielectric ceramic compositions that include magnesium (“Mg”), calcium (“Ca”), and titanium (“Ti”), are widely used in dielectric filters, dielectric resonators, and dielectric couplers in various types of radio frequency (“RF”) and microwave systems. However, a conventional dielectric ceramic composition that comprises Mg, Ca, and Ti, typically has a narrow sintering temperature range and exaggerated grain growth. Since the narrow sintering temperature range is difficult to maintain in the sintering kiln, the conventional dielectric ceramic may be under-fired (i.e. sintered at a temperature below a desired temperature range) or over-fired (i.e. sintered at a temperature above the desired temperature range) in the sintering kiln. However, under-firing and over-firing can cause various problems in the resulting dielectric composition.
For example, under-firing can cause undesirable variations in the dielectric constant, low density, and reduced mechanical strength in the conventional dielectric ceramic. On the other hand, for example, over-firing can cause undesirable exaggerated grain growth, which can also reduce the mechanical strength of the conventional dielectric ceramic composition. Furthermore, under-firing or over-firing caused by a narrow sintering temperature range results in low manufacturing yield for the conventional dielectric ceramic composition.
Thus, there is a need in the art for a dielectric ceramic composition that has an increased sintering temperature range, reduced exaggerated grain growth, and increased manufacturing yield.